Funded by a DOD IDEA grant, this project is testing the effects of several energy balance modulations (including various levels of calorie restriction (CR), exercise and combination regimens of CR and exercise) on spontaneous mammary tumorigenesis. The model system used is the female Wnt-1 transgenic mouse with and without p53 deficiency. A mechanistic focus is on the IGF-1 pathway, and the impact of p53 gene dosage, as well as a microarray exploration of unknown pathways underlying the protective effects of these obesity-preventing regimens is also underway.